A reconfigurable, wideband, and low profile circular polarization (CP) antenna is presented. Its wideband CP reconfigurability is realized by incorporating RF switches in a cross-bowtie radiator. A compact, wide bandwidth, and polarization independent artificial magnetic conductor (AMC) ground plane is developed to minimize the overall profile of the antenna while maintaining its wide bandwidth. The simplicity of this single element design facilitates the realization of a reconfigurable, wide bandwidth CP array that achieves higher directivity without changing its overall profile. Prototypes of the single element and of a 1×4 array of these elements were fabricated and tested. The measured results for both prototypes are in good agreement with their simulated values, validating their design principles. They are low profile with a height ~ 0.05 λ0. The array exhibits a wide fractional operational bandwidth: 1.65 GHz (21.7%), and a high realized gain: 13 dBic. Since they would enhance their channel capacity and avoid polarization mismatch issues, these reconfigurable CP antenna systems are very suitable for modern wireless systems. Index Terms-Artificial magnetic conductor (AMC), circular polarization, crossed dipoles, PIN diodes, reconfigurable antennas, widebandwidth I. INTRODUCTION Reconfigurable antennas have become increasingly more popular because they provide multi-functional characteristics, including variable frequencies, patterns, and polarizations in compact, lightweight , and cost-effective packages [1]-[7]. Reconfigurable circular polarization (CP) systems, i.e., those that can switch between left-handed (LHCP) and right-handed (RHCP) CP states, offer several unique and highly desirable characteristics. This reconfigurability facilitates the enhancement of the system capacity [8], avoids polarization mismatch [9], and enables polarization coding for wireless systems [10]. Fig. 1 illustrates such capacity enhancement in a satellite communication system. Thanks to the orthogonality of the two CP states, two separate channels can operate in the same frequency band for distinctive applications. For example, the LHCP carrier signal at f 0 could handle positioning or data transfer tasks while the RHCP carrier signal at the same frequency could be used for telecommunications. Thus, the system's capabilities are doubled. Furthermore, it is acknowledged that the operating bandwidth of the system is another key factor that determines the system capacity. Consequently, CP reconfigurable antennas with wide bandwidth and high directivity are desirable for these aforementioned applications and many others. Many efforts have been made to realize CP reconfigurability by either adopting switchable feed networks [11]-[15] or designing reconfigurable radiators [16]-[22]. However, the critical challenge has been the associated narrow operating bandwidths. The widest realized CP-operation fractional bandwidth among the above designs is only 7%. The fundamental bandwidth limitations of these antennas are associated with the...